1.1 Strimvelis is recommended, within its marketing authorisation, as an option for treating adenosine deaminase deficiency–severe combined immunodeficiency (ADA–SCID) when no suitable human leukocyte antigen-matched related stem cell donor is available.
Why the committee made this recommendation
ADA–SCID is a rare and serious condition that is fatal if untreated, and which severely affects the quality of life of people with the condition and their families. Treatment for ADA–SCID includes haematopoietic stem cell transplants (HSCTs). Clinical trial evidence shows that Strimvelis is effective in treating ADA–SCID. Compared with HSCTs, results suggest the main benefits are that more people live after Strimvelis than after a transplant and fewer people develop graft-versus-host disease. However, the exact size of the clinical benefits are uncertain because the trials have been small and uncontrolled, and the evidence for HSCTs is limited.
There are also several important uncertainties in the cost-effectiveness results associated with Strimvelis. However, there are health-related and wider benefits not included in the economic analysis but which are important to consider. Taking these into account, and considering the additional weight that can be assigned to the benefits when the estimated health gain is large, the plausible cost-effectiveness estimates for Strimvelis are within the range that NICE normally considers acceptable for highly specialised technologies.
The cost of Strimvelis is high and there are some uncertainties in the evidence. However, Strimvelis is likely to provide important benefits for people with ADA–SCID, at a cost that provides value for money in the context of a highly specialised service.